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Newly-Rebuilt 700R4 Blew After a Month

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digitalepiphany

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Location
Mesquite, TX
I had my 700R4 rebuilt by a guy in Lubbock named Crump. I got it back July 11 (last month). I moved back to the Dallas area on the 1st of this month. The next day, the transmission blew. This has been confirmed by a transmission guy that's local to me in Dallas. Now, I have to get my truck back to Lubbock so Crump can fix it (it has a warranty).
Fourwheelerjeff offered to tow it for me for the cost of diesel and lunch, but that's still gonna cost $300. I guess that's better than paying for an all new rebuild, but still.

Anyway, I've gotten conflicting information from both transmission guys (in Lubbock and Dallas). I don't know jack about transmissions, so they both seem to be making sense to me when they talk to me. However, I thought I'd run this stuff by those of you that know anything about transmissions. Any help would be greatly appreciated.

  1. Year - My truck had the original '84 trans in it when I took it to Crump to be rebuilt. He told me that any 700R4 before '87 was just a grenade waiting to go off. He said that he could rebuild mine, but I'd wind up with other issues down the road. Instead, he suggested that I have him rebuild one from '87-'91 because they're more reliable.

    The guy here in Dallas has the complete opposite point of view. He said the older ones are more reliable because they don't have an auxiliary (whatever that is). He thinks that the auxiliary just provides one more point for failure, and that the older 700's are beefier. He even pointed out that people will build up the older ones to use in hot rods. He suggested that Crump may have just wanted my '84 trans so that he can make some money off it.

    I found this guy through Kain, who said that Crump came highly recommended from wheelers in the West Texas area. Crump has TONS of transmissions lying around. I just don't see him keeping my old one just to make some extra money. But, the guy in Dallas has also been shooting straight with me so far, so I really have no idea who I should believe.
  2. Shift Kit - Before Crump rebuilt a 700R4 for me, I asked him about a shift kit. He said that the 35's I have on my truck don't really warrant a shift kit, so he didn't add a shift kit.

    The guy here in Dallas said the complete opposite, that because I have larger tires I should have at least a mild shift kit installed.

    So, what's the deal with shift kits? Do I need one? I'd like to know whether I need one or not before I have Crump rebuild this transmission for the second time.


So, basically, I'm confused. I have two transmission guys who seem to know what they're talking about telling me two completely opposite things.
 
79rustyk10 said:
I was under the impression the 87-91 were the best, with newer always being better.
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+ 1 for this.

The 87-91's were gone back over and have a few minor changes and fixes. They are the better base trans.

I don't see why a shift kit would be "needed" with 35's. Especially if you have a stock motor and have no issues with the trans overheating or shifting badly.

However, I personally would want one as they are not that expensive and would probably benefit the trans regardless of tires size.
 
The guy here in Dallas said that I should have Crump rebuild my old transmission, and get rid of the one that's in the truck now.

So, on year, we have Crump 1, Blair's 0.

Thanks.
 
Year: Crump 2, Blairs 0
Shift kit: Crump 0.5, Blairs 0.5

Thanks for the info. Makes me feel much better about Crump. Now I just need to find $400-500 to get it back to Lubbock. Hopefully I can get this thing heading back to Lubbock by next week.

I just think it sucks that the clutches are shot after less than a month. Speaking of which, I have to press the shifter forward to get it into reverse. It still won't move in reverse, but I never had to press it forward before. Is this just because the clutches are shot? Will this be something I'm going to have to keep doing, even after I get it rebuilt again?

Also, are there any upgraded parts I should ask Crump to use when he rebuilds it again? I don't mind paying a little extra now so that I can avoid having to ship this back to Lubbock again.
 
digitalepiphany said:
Year: Crump 2, Blairs 0
Shift kit: Crump 0.5, Blairs 0.5

Thanks for the info. Makes me feel much better about Crump. Now I just need to find $400-500 to get it back to Lubbock. Hopefully I can get this thing heading back to Lubbock by next week.

I just think it sucks that the clutches are shot after less than a month. Speaking of which, I have to press the shifter forward to get it into reverse. It still won't move in reverse, but I never had to press it forward before. Is this just because the clutches are shot? Will this be something I'm going to have to keep doing, even after I get it rebuilt again?

Also, are there any upgraded parts I should ask Crump to use when he rebuilds it again? I don't mind paying a little extra now so that I can avoid having to ship this back to Lubbock again.
Click to expand...

I would ask for a list of pressures in different gears and check them my self after the rebuild this time to make sure the T.V. cable was set correctly.
 
Heavier duty servos, HD sun shell housing, high quality band. I'm sure other guys will have other ideas too.
 
Any idea how much extra some of this will cost? Ballpark is fine. His labor will be free, but I'm sure he'll charge full price for heavy-duty parts, rather than just the difference between the heavy-duty parts and the parts he would normally use.
 
Obviously, that'd be my cheapest option. But, he's rebuilt it once already and it quit in less than a month. I just want to make sure that I don't have to spend another $300+ to ship it back to Lubbock again.
 
AFTER he rebuilds and you know its right, it id ask him that and how is he going to remberse you forhaving to tow it back to lubbock?
 
Kain said:
AFTER he rebuilds and you know its right, it id ask him that and how is he going to remberse you forhaving to tow it back to lubbock?
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Unless it specifically states he will cover expenses for bringing the vehicle back. I am sure he will tell him to go pound sand. Pretty sure almost no warranties cover those expenses.
 
metalneverdies said:
Unless it specifically states he will cover expenses for bringing the vehicle back. I am sure he will tell him to go pound sand. Pretty sure almost no warranties cover those expenses.
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^^This

Bowtie Overdrive, Monster Trans....none of them will reimburse for labor, so why would Crump reimburse for getting my truck back to Lubbock?
 
I've read the earlier versions of the 700R4 had less splines on the input shaft (I think 21 vs 27 on later ones after '87)..and had some problems with pressures not being sufficient to hold the clutches fully engauged..somewhere in my pile of books I have a step by step overhaul manual for one,that shows how to drill out some valve to boost the pressure up...

The '87 and up ones had the upgraded input shaft with more splines,and an auxillary valve body,and are supposedly much better than the early versions..that said,most of the ones I have seen seem to fail right around the 100,000 to 150,000 mile range regardless of the vintage..the one I have in my '85 K10 Suburban now loses reverse after a 20 mile ride and doesn't want to upshift into overdrive,or stay in,if it does--it has 155,000 on it roughly..

From what I have seen personally and read,most of the 700R4's that are rebuilt with just new clutches and seals,etc,and not had a new sunshell and some other parts added that are beefier than the stock ones,your going to be having troubles sooner than later...I think a lot of rebuilds fail because the case is worn and or has a hidden internal crack in the valve body passages..
 
Thanks for the info. I'll ask him exactly what he replaces on a rebuild. If I have to pay extra to have other things replaced, I'd rather do it now.

diesel4me said:
I've read the earlier versions of the 700R4 had less splines on the input shaft (I think 21 vs 27 on later ones after '87)..and had some problems with pressures not being sufficient to hold the clutches fully engauged..somewhere in my pile of books I have a step by step overhaul manual for one,that shows how to drill out some valve to boost the pressure up...

The '87 and up ones had the upgraded input shaft with more splines,and an auxillary valve body,and are supposedly much better than the early versions..that said,most of the ones I have seen seem to fail right around the 100,000 to 150,000 mile range regardless of the vintage..the one I have in my '85 K10 Suburban now loses reverse after a 20 mile ride and doesn't want to upshift into overdrive,or stay in,if it does--it has 155,000 on it roughly..

From what I have seen personally and read,most of the 700R4's that are rebuilt with just new clutches and seals,etc,and not had a new sunshell and some other parts added that are beefier than the stock ones,your going to be having troubles sooner than later...I think a lot of rebuilds fail because the case is worn and or has a hidden internal crack in the valve body passages..
Click to expand...
 
From what I've heard the 700r4's are a lot trickier to rebuild well, than a lot of autos. IMO the parts I listed, should really be included in a good rebuild. If nothing else the HD sun shell is a must. I think that's the most common mechanical fail point. I'd second the pressure readings too.
 
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